Number of (w,x,y,z) with all terms in {1,...,n} and w > |x-y| + |y-z|.

Terms

a(0) =0a(1) =1a(2) =8a(3) =35a(4) =104a(5) =247a(6) =504a(7) =925a(8) =1568a(9) =2501a(10) =3800a(11) =5551a(12) =7848a(13) =10795a(14) =14504a(15) =19097a(16) =24704a(17) =31465a(18) =39528a(19) =49051a(20) =60200a(21) =73151a(22) =88088a(23) =105205a(24) =124704a(25) =146797a(26) =171704a(27) =199655a(28) =230888a(29) =265651